Presently bodies moving in fluid medium velocity measurements are proceeded in laboratory to evaluate the body's hydrodynamic lines, moving resistance areas and fluid-friction losses. The tests simulate the body's relative movement related to the fluid. The body stays put and the fluid flows around. The measurement instruments and gauges being used in laboratory simulated tests do not apply on measurements when the body is a surfboard and is moving in real time and places. Presently “field” measurements can not be done, i.e., with the surfboard moving in real time and places, by not existing measurement apparatus that being affixed to the surfboard wouldn't significantly impair nowadays outstanding parameters to the surfboard performance such as the surfboard own weight, motion resistance, surfer's positioning and others.